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The Bearing Basis Note

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Kent McMillan
(@kent-mcmillan)
Posts: 11419
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From time to time, I see notes describing the basis of bearings used on a map or written description that are almost in a class by themselves. Today's winning entry was:

BEARING BASIS: NAD83 (1993) - BASED ON THE OCCUPATION OF N.G.S. MONUMENT "CARPENTER", (PID BM0921) SHOWN ON U.S.G.S. QUAD - MOUNTAIN CITY (1986)

 
Posted : April 1, 2016 5:06 pm
Warren Smith
(@warren-smith)
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Wow, just wow! They are in a class by themselves!

 
Posted : April 1, 2016 5:19 pm
nate-the-surveyor
(@nate-the-surveyor)
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I like the one that said:
Basis of Bearings: GPS, taken on July 10, 2013.....
(What does the date have to do with it, and what did you do...) Left that one hanging.

N

 
Posted : April 1, 2016 8:01 pm
Timberwolf
(@timberwolf)
Posts: 72
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Where's that "scratching my head" icon when you need it...

 
Posted : April 1, 2016 8:25 pm
Williwaw
(@williwaw)
Posts: 3424
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What's your standard BOB statement? Just curious. I agree that alone would be lame. Is there more?

Just because I'm paranoid, doesn't mean they aren't out to get me.

 
Posted : April 1, 2016 9:00 pm

Kent McMillan
(@kent-mcmillan)
Posts: 11419
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Topic starter
 

Williwaw, post: 365215, member: 7066 wrote: What's your standard BOB statement? Just curious. I agree that alone would be lame. Is there more?

No, that was the statement as to basis of bearings reproduced in its entirety. It amounted to: "I set up my RTK base at this control point thing and pushed the button".

As to the basis of bearings note I use, it's typically along the lines of this note from a written description:

"Bearings of Lines refer to Grid North of the Texas Coordinate System of 1983 (South Central Zone) as computed from GPS vectors".

The "as computed from GPS vectors" bit is just a clue that basically the bearings refer to an essentially exact determination of the direction of grid North, not one determined by conventional survey from triangulation stations or calculated from near-geodetic North obtained from solar observations.

 
Posted : April 1, 2016 9:23 pm